It comes despite the House of Lords on April 12 voting in favour of banning the detention of pregnant women in immigration centres.

Ahead of the announcement, Home Secretary Theresa May said the Government takes "the welfare of detainees very seriously".

"That is why I commissioned Stephen Shaw to carry out an independent review of the welfare of vulnerable people in the detention estate, which was published earlier this year," she said.

"We have listened to him and to others in Parliament and beyond in shaping a humane system that will effectively end the routine detention of pregnant women.

"This new approach and our wider reforms strike the right balance between safeguarding pregnant women and vulnerable people and maintaining effective and proportionate immigration control."

The reform follows an independent review into the welfare of immigration detainees by the former prisons and probation ombudsman, Mr Shaw.

His report called for a complete ban on the detention of pregnant women in immigration centres such as Yarl's Wood - of which there is currently no law against.

But under the new proposals, the Home Office would still retain the ability to hold pregnant women for short periods of time.

This would include instances such as at the border, in order to remove them quickly if they have no right to stay in the UK, or if they present a risk to the public.

Detention could only be extended beyond the three-day limit with ministerial approval, and pregnant women could only then be held for up to a week in total.

Reacting to the announcement, Refugee Council advocacy manager, Anna Musgrave, said: "It's disappointing that the Government has chosen to defy the Lords, defy public opinion and defy common sense by choosing to continue imprisoning pregnant women.

"Pregnant women with insecure immigration status are far more likely to die during childbirth or lose their babies than British women.

"Women who already have such high risk pregnancies shouldn't be detained under any circumstances: there's absolutely no excuse for compromising the health and well being of a mother and her baby."

In addition to this, the current development of the adults at risk policy within the reform, would mean vulnerable people would also not be detained unless it was absolutely necessary.

The new legislation will be tabled when the Immigration Bill returns to the House of Commons later this month, and if passed, will commence once royal assent has been given.